Stable cellular force measurement by on-chip robotic probe by employing surface-directed liquid flow

This paper presents a novel on-chip manipulation method of a single cell using a surface-directed liquid flow. In order to avoid the oscillation disturbance due to the motion of on-chip robotic probe, air-liquid interface separated the driving point from the on-chip probe, and only manipulation point approached cell in the microchannel. The surface-directed liquid flow was formed by the nanopillar micropatterns fabricated by the multi-scale patterning technique. Wide range wettability control of the substrate was achieved by changing the density of nanopillars to obtain the robust air-liquid interface. The oscillation of microparticles was dramatically reduced by the surface-directed liquid flow. Finally, the cellular force measurement, which required the stable cell manipulation, was achieved.